Effect of calcia co-doping on ceria-stabilized zirconia

Abstract

© 2018 Elsevier Ltd. Ceria-stabilized zirconia ceramics are characterised by excellent hydrothermal stability and high fracture toughness, but the fracture strength and hardness are lower than that of conventional 3Y-TZP, which is sensitive to low temperature degradation in humid environments. In the present work, the influence of small concentrations of calcia on the microstructure, mechanical properties and hydrothermal ageing resistance of 10 and 12 mol% CeO2 stabilised ZrO2 has been assessed. The addition of only 1 mol% of CaO had a strong refining effect on the microstructure resulting in an increased hardness and strength but reduced stress activated tetragonal-to-monoclinic transformability. The addition of 3 mol% CaO however enhanced the transformability with respect to 1 mol% CaO and preserved the high resistance to hydrothermal degradation of Ce-TZP.Peer ReviewedPostprint (author's final draft

Mechanical properties of ceria-calcia stabilized zirconia ceramics with alumina additions

“…In terms of grain size, the zirconia average grain size decreases with the presence of calcia from ⁓ 2 µm in pure 10Ce-TZP to 1.2 µm in 10Ce-1CaO (See Table 2). This reduction in grain size is not as large as reported in previous works by Turon-Viñas et al [34] (i.e., ⁓0.5 µm) and Tovar-Vargas et al [27] (i.e., ⁓0.6 µm). In these two works, the powders were processed by milling and dried trough rotary evaporator following by steaming, instead of applying a slip-casting drying step.…”

“…The physical properties of the starting powders for 10Ce-TZP and α-alumina have been described elsewhere [33]; the mean particle sizes after stirring in water for five days were 250 and 270 nm, respectively. The mean particle size of the CaO powders was in the range of 10-35 µm as observed by scanning electron microscopy (SEM) [34].…”

“…* Values reported by El Attaoui [37], ** Value reported by Turon-Vinas et al [34], † Four-point bending test, ⁑ 490 N load, § Three-point bending test…”

Sinterização, microestrutura e condutividade elétrica da zircônia estabilizada com céria

“…Os efeitos da co-dopagem da Ce-TZP com calcia (CaO) foram investigados por Turon-Vinas et al [18]. A adição de apenas 1% em mol de CaO teve um forte efeito de refino na microestrutura, resultando em um aumento da dureza e resistência, mas com redução da capacidade de transformação tetragonal para monoclínica ativada por tensão.…”

“…A adição de apenas 1% em mol de CaO teve um forte efeito de refino na microestrutura, resultando em um aumento da dureza e resistência, mas com redução da capacidade de transformação tetragonal para monoclínica ativada por tensão. A adição de 3 mol% de CaO, entretanto, aumentou a capacidade de transformação em relação à composição com 1 mol% e preservou a alta resistência à degradação hidrotérmica característica da Ce-TZP [18].…”